U.S. patent application number 13/960416 was filed with the patent office on 2014-02-13 for ocular collar stent for treating narrowing of the irideocorneal angle.
This patent application is currently assigned to RegenEye, L.L.C.. The applicant listed for this patent is RegenEye, L.L.C.. Invention is credited to Peter Renke.
Application Number | 20140046437 13/960416 |
Document ID | / |
Family ID | 50066775 |
Filed Date | 2014-02-13 |
United States Patent
Application |
20140046437 |
Kind Code |
A1 |
Renke; Peter |
February 13, 2014 |
Ocular Collar Stent for Treating Narrowing of the Irideocorneal
Angle
Abstract
An ocular stent for insertion in an anterior chamber of an eye
is provided. The stent facilitates the restoration of the structure
of an irideocorneal angle of the anterior chamber for treating
structural changes from ocular aging. The stent includes an annular
body sized to fit in the irideocorneal angle of the eye. The body
includes: an anterior portion configured to contact a surface of a
transition zone between a trabecular meshwork and a corneal
endothelium of the eye; a posterior portion configured to contact a
peripheral iris of the eye; and a central portion connecting the
anterior portion and the posterior portion of the body. A method
for stabilizing the iredeocorneal angle of the anterior chamber
using a stent is also disclosed herein.
Inventors: |
Renke; Peter; (Vancouver,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RegenEye, L.L.C. |
Point Roberts |
WA |
US |
|
|
Assignee: |
RegenEye, L.L.C.
Point Roberts
WA
|
Family ID: |
50066775 |
Appl. No.: |
13/960416 |
Filed: |
August 6, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61680453 |
Aug 7, 2012 |
|
|
|
Current U.S.
Class: |
623/4.1 |
Current CPC
Class: |
A61F 2/14 20130101; A61F
9/013 20130101; A61F 2/142 20130101; A61F 9/007 20130101; A61F 2/82
20130101; A61F 9/00781 20130101 |
Class at
Publication: |
623/4.1 |
International
Class: |
A61F 2/14 20060101
A61F002/14 |
Claims
1. An ocular stent for insertion in an anterior chamber of an eye,
the stent comprising an annular body comprising: an anterior
portion configured to contact a surface of a transition zone
between a trabecular meshwork and a corneal endothelium of the eye;
a posterior portion configured to contact a peripheral iris of the
eye; and a central portion connecting the anterior portion and the
posterior portion of the body.
2. The stent of claim 1, wherein the anterior portion of the
annular body is also configured to contact at least a portion of an
anterior portion of the trabecular meshwork.
3. The stent of claim 1, wherein the anterior chamber comprises an
irideocorneal angle and the annular body is receivable within the
irideocorneal angle.
4. The stent of claim 3, wherein a portion of the posterior portion
of the body extends around the irideocorneal angle and crosses an
anterior chamber exposure of a ciliary body up to or beyond a
scleral spur of the eye.
5. The stent of claim 1, wherein at least a portion of the body
defines a cross section having a boomerang shape.
6. The stent of claim 1, wherein at least a portion of the body
comprises a shape memory material.
7. The stent of claim 1, wherein the body is configured to span at
least a portion of the trabecular meshwork.
8. The stent of claim 1, wherein the body comprises:
polymethylmethacrylate (PMMA), silicone or acrylic block polymers
materials having PMMA components, hydrophobic acrylics, hydrophilic
acrylics, acrylic poly(styrene-block-isobutylene-block-styrene),
silicon elastomer, or heparin surface modified acrylics.
9. The stent of claim 1, further comprising a coating on the
surface of the body, wherein the coating is formed from a material
that increases at least one of biocompatibility or durability of
the stent.
10. The stent of claim 1, wherein the body further comprises at
least one communication structure extending radially through the
body for equalizing fluid pressure across the body.
11. The stent of claim 1, wherein the anterior portion of the body
comprises beads or texturing extending from the anterior
portion.
12. The stent of claim 11, wherein the beads or texturing is
configured for variable contact between the body and the surface of
the transition zone.
13. The stent of claim 1, wherein, when the ocular stent is
inserted in the anterior chamber of the eye, the central portion of
the body is positioned opposite the trabecular meshwork.
14. The stent of claim 1, wherein when the ocular stent is inserted
in the anterior chamber of the eye, the central portion of the body
is positioned adjacent to the irideocorneal angle and is configured
such that an angle of the central portion approximately corresponds
to the irideocorneal angle.
15. The stent of claim 14, further comprising an o-ring that
contacts at least a portion of the central portion of the body, and
an anterior chamber interocular lens coupled with the o-ring.
16. The stent of claim 1, wherein the stent is at least one of
foldable and rollable, such that the stent can be at least one of
folded or rolled during insertion and unfolded or unrolled once
inserted in the anterior chamber.
17. An ocular stent for insertion in an anterior chamber of an eye,
the stent comprising: at least one annular cord; a plurality of
anterior arms extending from the cord in a first direction; and a
plurality of posterior arms extending from the cord in a second
direction, the second direction being different than the first
direction, wherein the stent is receivable within an irideocorneal
angle of the anterior chamber of the eye, and wherein the anterior
arms and the posterior arms together form an articulating
joint.
18. The stent of claim 17, wherein at least one of the posterior
arms and the anterior arms defines at least one through hole and
wherein the cord is inserted therethrough, thereby connecting the
at least one arm to the cord.
19. The stent of claim 18, wherein at least one of the through
holes is a slotted through hole for limiting the range of motion of
the joint.
20. The stent of claim 17, wherein the anterior arms and the
posterior arms alternate along the at least one cord.
21. A method of stabilizing an irideocorneal angle of an anterior
chamber of an eye, the method comprising: inserting a stent into
the anterior chamber, such that the stent is in contact with soft
tissue of the anterior chamber; and simultaneously applying
pressure in an anterior direction to a surface of a transition zone
between an anterior limit of a trabecular meshwork and a posterior
limit of a corneal endothelium of the eye with an anterior portion
of the stent and applying pressure in a posterior direction to a
surface of the peripheral iris of the eye with a posterior portion
of the stent.
22. The method of claim 21, wherein inserting the stent comprises:
forming an incision in a cornea of the eye for accessing the
anterior chamber; inserting a portion of an injector into the
anterior chamber through the incision; and expelling the stent from
the injector to the anterior chamber for placement.
23. The method of claim 21, further comprising directing aqueous
humor fluid before the fluid enters the trabecular meshwork by
passing the fluid through the stent.
24. The method of claim 21, further comprising stimulating stem
cells located within the transitional zone as a result of pressure
applied by the anterior portion of the stent.
25. The method of claim 21, further comprising applying pressure to
at least a portion of an anterior portion of the trabecular
meshwork with the anterior portion of the stent.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/680,453 filed on Aug. 7, 2012, which is hereby
incorporated by reference in its entirety
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates broadly to a structure for insertion
in the anterior mammalian eye for treatment related to natural,
predictable aging changes. More particularly the invention relates
to a surgically implanted device for the human eye. The device
provides structural support to specific ocular anatomy as a means
to counteract changes naturally brought about by aging.
[0004] 2. Description of the Related Art
[0005] All human eyes go through physical changes as a result of
the normal aging processes. These changes affect various structures
of the eye. The human eye has three chambers. The largest is the
vitreous chamber. It is filled with the gelatinous material of the
vitreous body. This material fills the eye and principally serves
to maintain the shape of the eye. It also plays a role in
accommodation to anchor the posterior lens attachments and interact
with induced forces. In front of the vitreous chamber are the
posterior and anterior chambers. These chambers also play a role in
maintaining the shape of the eye through the mechanism of balancing
the production and drainage of aqueous humor. This fluid fills both
chambers, which are separated by the iris. The pupil is the area of
communication between the two chambers. The aqueous humor is
produced by the ciliary body in the posterior chamber and then
circulates forward through the pupil to the anterior chamber. The
fluid then slowly filters through the annular structure of the
trabecular meshwork and its distal system. The anterior chamber is
demarked by the cornea and iris. The boundaries of the posterior
chamber are the iris and anterior lens capsule. The posterior
chamber peripherally reaches to the ciliary body, which is the
location of the musculature and apparatus attachment responsible
for accommodation.
[0006] Accommodation involves constriction and relaxation of the
ciliary muscles to achieve the control of focus. The process of
accommodation is naturally controlled by the brain. It is an
automatic process that results in clear vision by manipulation of
the lens shape and position to focus light on the retina. The eye
goes through a predictable degradation of accommodation with aging.
The focusing apparatus becomes progressively more flaccid over
time. The musculature and feedback mechanism remain intact, but the
ability to actuate change and focus diminishes throughout life,
until it is essentially totally ineffective. This process is known
as presbyopia. The youthful eye has excessive ability to
accommodate in the order of tenfold of what is generally required.
This surplus erodes over time, and usually reaches the threshold of
being initially problematic at 40 to 45 years old. The degradation
continues to progress and usually renders the eye with complete
inability to sustain any near focus by the age of 60. This is a
very relevant juncture with respect to the aging process of the eye
and subsequent prevalence of various disease processes as they
manifest. These predictable changes result in an anterior shifting
of the lens and focusing apparatus. The lens and apparatus are
attached by micro ligaments known as zonules. The zonules become
progressively more flaccid with aging. The cause of this increased
flaccidity is likely two fold. The zonules simply stretch over time
due to perpetual use. This stretching is likely a contributing
factor, but aging changes to the actual lens is responsible for the
majority of change. These aging changes eventually manifest as
cataracts. Cataract development is a predictable and understood
change to the aging eye. The matrix of the crystalline lens becomes
cloudy and impairs vision. This typically becomes problematic
enough to require cataract surgery between the ages of 70 to 80. As
part of the process the lens stiffens, thickens, and subsequently
increases in diameter. This increase in diameter results in outward
displacement of the zonule attachments. The entire focusing system
becomes relatively slack and displaces forward. The thickening of
the lens also compounds these forward forces as the vitreous body
pushes the structures from behind. Surgically removing the cataract
becomes necessary and is common practice.
[0007] At the stage prior to surgery, the intact aged eye has to
maintain function with very unfavourable displaced and compressed
anatomy. The prevalence of various eye diseases begins to increase
dramatically after the first five decades of life. These diseases
include, but are not limited to, glaucoma, Fuchs' corneal
dystrophy, and retinal detachments. These three diseases are
discussed herein, as each disease relates to forward shifting
anatomical changes. Presbyopia and refractive error are also
discussed, but are not considered to be diseases.
[0008] Glaucoma is a disease which is diagnosed by evidence of
vision loss or measured change to the optic nerve and the retinal
nerve fiber layers. It is estimated that over 4 million Americans
have glaucoma, but only half of the people who suffer from the
disease are aware of their condition. Approximately 120,000 people
are blind as a result of the disease. Glaucoma is the second
leading cause of blindness in the world. Estimates put the total
number of suspected cases of glaucoma at about 70 million
worldwide. Glaucoma is a group of diseases that relate to
intraocular pressure (TOP) and the aqueous humor fluid dynamics of
the eye. It is a balance between the rate of aqueous production
from the ciliary body in the posterior chamber and drainage via the
trabecular meshwork and its distal system located in the anterior
chamber. It is estimated that the ciliary body produces aqueous at
an average rate of 2-3 micro liters per minute which translates
into about 1.5 liters per year. There are variations in rates of
production; however, these fluctuations are likely not as
significant as the ability to drain the fluids, to balance
pressure. The aging of the eye results in a predictable anterior
shift of the structures posterior to the trabecular meshwork. This
shift results in restriction of flow based on the structural
change. Evidence of this shift is observed clinically when a
cataract is surgically removed. On average, there is a 17% decrease
in intraocular pressure (TOP), shortly after surgery. The anterior
chamber angle instantly widens upon removal of the lens. The
structure of the trabecular meshwork is able to open under these
favourable changes. The trabecular meshwork is a mesh-like
structure of tapering pores that direct the fluids into Schlemm's
canal. The natural architecture of this porous tissue cannot
perform its function well under compression. Glaucoma patients
often undergo cataract surgery prematurely to take advantage of the
drop in baseline IOP. Cataract surgery could be delayed or avoided
in many cases where the need for the operation is driven by the
pressure reduction aspects. The visual complications of natural
aging cataracts are generally noticed by one's early sixties.
Vision continues to decline typically requiring cataract surgery at
ages ranging from early to mid seventies. The average life
expectancy in the United States from birth is 78. It is more
relevant to consider that the average life expectancy from an age
of 63 is 20 years. Thus, a significant portion of the population
does not live long enough to require cataract surgery based on
vision needs.
[0009] Although glaucoma is a group of diseases, it can generally
be classified into two categories: closed angle and open angle
glaucoma. Closed angle glaucoma is a medical emergency when the
angle is truly closed. This occurs when the peripheral iris
occludes the trabecular meshwork. Topical and systemic
pharmaceutical agents must be employed and often an emergency
iridotomy is needed. An iridotomy involves making puncture-like
openings through the iris without the removal of iris tissue. It is
performed either with standard surgical instruments or a laser. The
iridotomy allows for instant equalization of IOP between the
anterior and posterior chamber.
[0010] Primary Open Angle Glaucoma (POAG) accounts for the majority
of glaucoma cases. It presents with an apparently open drainage
structure and often normal intraocular pressures. It is
characterized by progressive optic neuropathy resulting in atrophy
of the optic nerve and the nerve fiber layers. The disease process
must have factors that are not apparent upon superficial anatomical
observation and clinical IOP measurements. It is well documented
that IOP fluctuates. Animal studies where IOP measuring probes have
been implanted have demonstrated very dramatic results. Rabbit and
monkey subjects produced TOP spikes in the order of 90 mmHg. This
represents pressure almost six times normal values. This highlights
the necessity of IOP clearing time for these spikes to maintain eye
health. The eye must be able to sustain brief spikes in IOP.
Sneezing and rubbing one's eyes would be examples of normal acute
IOP spikes. Early POAG cases are likely, in part, the inability of
the eye's drainage system to facilitate a safe pressure clearing
time. In these open angle cases the trabecular meshwork structure
would be initially compressed internally and out of superficial
view. This coincides with the stage of rapid decline in loss of
accommodation at the age of 50 to 60. This directly correlates to
the age where the incidence of glaucoma dramatically increases. The
angle is internally compressing in the periphery as the ciliary
body and its structures shift forward. The angle and whole anterior
chamber are narrowing. The farther forward the structures shift,
the greater the zonular flaccidity. As this progresses there is
less pulling on the anatomy adjacent to the trabecular meshwork,
which is known to decrease IOP. The action of pilocarpine eye drops
utilizes this mechanism to lower IOP. Pilocarpine also acts on the
ciliary muscle and causes it to contract. When the ciliary muscle
contracts, it opens the trabecular meshwork through increased
tension on the scleral spur at the base of the trabecular meshwork.
This narrowing trend becomes more apparent 10 to 20 years later
with significant cataract development. The central thickening of
the lens produces additional forward movement that is more evident
on clinical observation.
[0011] In general the disease process is treated by isolated
approaches to certain aspects of the disease. Pharmaceutical agents
represent the primary form of treatment. They work on modulating
production or drainage of the aqueous fluids. These therapies are
hindered by costs, compliance and side effects. Managing drug side
effects in an elderly population is difficult.
[0012] Tissue modifying procedures without device implantation have
traditionally been secondary or complimentary approaches to the
pharmaceuticals. These surgical procedures include trabeculectomy
and laser trabuculoplasty. Trabeculectomy is very invasive surgery
with considerable side effects. Scarring of the treated area is the
greatest risk for failure. Antimetabolite and antineoplastic
medications are often needed to augment the procedure. Other risks
include infection, haemorrhaging, cataract formation, and hypotony.
With hypotony, if the pressure remains too low for prolonged
periods maculopathy and possible vision loss my result. Laser
trabuculoplasty is more widely utilized because of its less
invasive nature. Both procedures have very limited success and
usually still require chronic paramedical use. All procedures which
involve surgical trauma to compromised tissues must contend with
the tissue's natural healing mechanism. The early positive response
often renders a compromised eye at greater risk for failure. There
is a shift now to improved surgical procedures as a primary
treatment. An effective single procedure has the potential to
reduce costs and eliminate compliance issues. Most devices
available as treatments are focused on by-passing or bridging
elements of the drainage pathway. The development and improvement
of glaucoma shunts or stents remains a very active field of
investigation. The ultimate goal is to have a single surgical
procedure as a first line treatment. There are various shunt
designs that continue to evolve. The basic principle is to bypass
the resistance of the trabecular meshwork and allow flow of the
aqueous humor directly into the Schlemm's canal. If the shunt can
remain clear, the pressure in the anterior chamber will remain
equalized with the pressure in Schlemm's canal. From there on, the
uveoscleral outflow pathway remains intact to modulate IOP. The
surgical implantation of such a small stent requires the extreme
precision of a skilled surgeon. It is also difficult to be
confident that the stent has penetrated the tissues as required to
be effective. The lumen of the stent must remain open. The risk of
scarring and blockage will always be of concern for patency.
[0013] All glaucoma treatments and variations of treatments have
notable disadvantages and limited success. Medication has
significant side effects and surgery results in tissue trauma. In
both cases, the cost of treatment is high. The average direct cost
of glaucoma treatment ranges from $623 per year for patients in the
earliest stages and in excess of $2,500 a year for end stages of
the disease. The annual total costs for glaucoma are approaching $3
billion in the U.S. economy alone. Procedural short term benefits
can often result in additional costs associated with failure and
complications. A true treatment for glaucoma is a common goal. The
drainage systems of the eye may be best left intact if it is
possible to provide assistance to circumvent the degenerative
process. Trauma and scarring will inevitably compound the
regenerative process. Implantation of a device to provide
structural support offers promise. It may be possible to cure
glaucoma through proactive prevention. Stem cell activity and
cellular regeneration in the trabecular meshwork also are likely
involved. A device to stimulate the responsible stem cells along
with structural support could provide the eye with all that is
necessary to prevent the manifestation of glaucoma.
[0014] Fuchs' Corneal Dystrophy is a group of degenerative diseases
of the corneal endothelium. The endothelium is a monolayer of
specialized, flattened, mitochondria-rich cells that line the
internal surface of the cornea. Fuchs' dystrophy is clinically
observed as an accumulation of focal outgrowths called guttae which
are a thickening of the Descemet's membrane. This results in
corneal edema leading to decreased vision and potentially vision
loss. It is estimated that 5-10% of the population over 50 years
old have clinically significant manifestation of the disease. The
underlying cause is a deficiency of corneal endothelial cells. The
density of endothelial cells on the posterior surface of the
corneal predictably decline with aging. There has been significant
research and discovery in the genetics of Fuchs' variants. There
are early and late onset variations, and women tend to be more
affected at an early stage. The common link to all is the decline
in endothelial cell density. Evaluation of the endothelium by
specular microscopy can demonstrate classic changes of Fuchs'
endothelial dystrophy. With the background of the invention in
mind, discussion will focus on the corneal endothelium and its
role. The principal physiological function of the corneal
endothelium is to allow nutrients from the aqueous humor to diffuse
into the superficial layers of the cornea, while at the same time
actively pumping water out of the cornea back into the anterior
chamber. Thus, the corneal endothelium effectively keeps the cornea
from becoming edematous and losing clarity. Treatment options vary
depending on severity of symptoms and state of disease progression.
Early treatments are targeted at reducing the edema. These
treatments include topical dehydrating agents, warm air to increase
evaporation, lowering IOP, and topical nonsteroidal
anti-inflammatory drugs. Treatment is necessary until it is not
possible to preserve good vision; at that point keratoplasty is
necessary. Penetrating keratoplasty (PK) has been the standard for
treatment of Fuchs' endothelial dystrophy. PK involves replacement
of the full corneal thickness with donor tissue, even though only
the endothelial layer is defective. In recent years, major advances
in this field have made replacement of only the endothelial layer
possible, without disturbing normal anterior structures of cornea
using endothelial keratoplasty. Both are effective procedures, but
often have complications and limited duration of effectiveness.
Approximately 10% of those identified with the dystrophy will need
keratoplasty. The purpose of transplantation is to increase
endothelial cell density and thus restore function. As a result, a
procedure that allows the eye to regenerate its own endothelial
cells may be an effective treatment option. Recently the stem cells
responsible for this have been located in the posterior limbus. At
this junction between the cornea and sclera, there is an area known
as the transition zone where stem cells believed to be responsible
for endothelial and trabecular meshwork cells reside. Schwalbe's
Line demarks part of the transition zone. The stem cells have been
observed to be stimulated after laser trabuculoplasty for glaucoma
treatment. Stem cells are known to be activated by trauma. In these
cases, the stimulation can be beneficial or detrimental if over
stimulated. Mechanical forces are also known to trigger stem cell
differentiation. The mechanical stimulation model may be very
significant with respect to corneal endothelium regeneration. The
link to a decline in endothelial cell density and age may very well
be correlated to a decline in accommodative ability. By the age of
45, approximately half of our endothelial cells and most of the
ability to accommodate have been lost. A child has potentially ten
times more accommodative ability than necessary. Such excessive
power to focus would translate into significant forces induced by
the ciliary muscles and accommodative apparatus. The transition
zone where the stem cells are located absorbs some of these forces.
It would be logical to expect certain level of cellular activity to
result. Implantation of a device to induce mechanical forces to the
transition zone would have the potential to stimulate stem cells.
The device will need to provide an appropriate amount of
stimulation by means of variable forces and contact area with the
transition zone. If a healthy population of endothelial cells can
be maintained, Fuchs' dystrophy should not manifest. The underlying
genetic predisposition will still exist, but induced mechanical
stimulation has the potential to prevent the disease symptoms from
manifesting.
[0015] Retinal Detachments are generally categorized into
idiopathic, traumatic, advanced diabetic, and inflammatory
disorders. The majority of disorders fall into the idiopathic
classification. This grouping of spontaneous retinal detachments
dramatically increases after the age of 40 and peaks at about the
age of 60. The bulk of these idiopathic detachments are
vitreoretinal in origin. The vitreous humor changes in consistency
with aging. Its boundaries shrink away from the retina. This
separation is known as a posterior vitreous detachment (PVD). As
the vitreous separates, it can pull the retina with it in areas of
excessive adhesion. The incidence of retinal tears resulting from a
PVD varies on average between 5% and 15%, depending on the
presentation. The process of the PVD can be asymptomatic or
symptomatic with photopsia. Flashes or sparks of light in the
absence of true light are indicative of tension at retinal
adhesions and present with greater risk. The symptoms usually
subside once the process resolves. Floaters may remain after the
process is complete. In the event that the adhesions does not
release, a retinal detachment is likely to occur. Retinal
detachments of this etiology have a particularly strong correlation
with the decline in accommodative ability. It is known that the
ciliary body remains active even with lack of any sustainable
accommodation. The feedback mechanisms to accommodate also remains,
but the cortical stimulation to accommodate is met with a lack of
response that ultimately can produce an over active muscular
response of the accommodative apparatus. The vitreous body and the
zonular attachments have a significant role in the apparatus. There
is debate over what is responsible for the ability to accommodate.
The exact combination of actions and reactions is not important for
the discussion of retinal detachment associated with PVD's. What is
significant is the balance of forces. When the ciliary body
contracts it relaxes the circumferential lenticular zonules. These
include the equatorial, anterior, and posterior zonular limbs The
area of traction exists along the anterior hyaloid of the vitreous
body. There are hyaloid zonules that anchor here and ultimately
transfer forces to retinal adhesions. The dramatic increase in
retinal detachment must have some relation to the actions of the
complex accommodative mechanism. When the eye has adequate
accommodative control, there is a balance between ciliary
contraction and relaxation. The accommodative mechanism would
predominately be in a relaxed state, when viewing beyond a few
feet. Effectively this state puts tension on the lenticular zonule
complex, pulling the lens back and relieving tension on the retinal
attachments. The opposite is true of the response to near focus.
The ciliary body contracts releasing tension on the lenticular
zonule attachments. The vitreous body and its gelatinous
characteristics push the lens forward to accommodate. The forward
movement is retained by tension transferred around the anterior
hyaloid and retinal attachments. With presbyopia the concern is how
the feedback mechanism responds to a lack of focus. The action and
reaction do not balance and cause instability. The ciliary body
easily can go into spasm under these circumstances. These spasms
can clinically present as ocular pain. The ciliary muscle may very
well become stronger as accommodative ability diminishes with
aging. The retinal adhesion will be put under significant traction
resulting in the inevitable PVD and risk of retinal detachment. The
relationship is complex and it is difficult to isolate the
components of the accommodative mechanism. Other tissue related
changes with aging must also be factors.
[0016] Retinal tears and detachments are treated by a variety of
procedures. Success of treatment is high if the detachment is
treated in a timely manner. When tears are seen clinically there
are generally two approaches, laser photocoagulation and cryopexy.
Both methods essentially scar the tissue around the tear to
stabilize it. Retinal detachments have more involved surgical
treatments. Pneumatic retinopexy is the least invasive. The
procedure involves injecting a gas bubble in the eye to float the
retinal back in place where it can reattach. Photocoagulation or
cryopexy are then used to stabilize any holes or tears. Scleral
buckling surgery is another surgical procedure. The surgeon places
a piece of silicone sponge, rubber, or semi-hard plastic on the
outer layer of the eye and sews it in place. This relieves traction
on the retina, preventing tears from proceeding to detachments, by
supporting the retina. The most invasive treatment is a vitrectomy.
This procedure involves removal of the vitreous body from the eye.
Vitrectomy gives the surgeon better access to the retina to repair
holes and close large tears.
[0017] A procedure that could restore a functional amount of
accommodation could reduce retinal traction by stabilizing
contraction of the ciliary muscles. The feedback would be restored
and the accommodative system would predominately be in a state that
relieves tension on the vitreous base and retina. To achieve this
reduction in retinal traction, the anterior displacement of the
whole system must be returned to a more posterior position. This
repositioning could be achieved through careful calculated sizing
and implantation of a device to provide structural support and
targeted appositional forces.
[0018] Refractive Error Correction encompasses a variety of
approaches to achieve clear vision. All eyes have a need for visual
assistance by optical or surgical procedures during a life time.
Emmetropia is the most common presentation. This is a state of
vision when one requires no optical aids to see clearly when
distant viewing. These individuals have no need for correction
until presbyopia sets in at mid life. This loss of accommodative
ability is true of all eyes regardless of distance refractive
status. The non emmetropic eyes can be divided into myopia or
hyperopia, respectively nearsighted or farsighted eyes. Astigmatism
is generally present in variable amounts. This represents an
unequal curvature of the cornea or internal lens of the eye. There
are infinite variations in refractive error and many treatment
options available. The most common treatments include spectacles
and contact lenses. Essentially all refractive errors can be
treated by variations of these solutions. There are many other
refractive modification procedures available. Mostly these
treatments are elective lifestyle procedures, but in some cases
medically necessary. Cataract surgery is an example of necessary
surgery. Cataract extraction is the most common surgical procedure
in the United States. There are two types of cataract surgery
commonly employed today. Standard extracapsular cataract extraction
involves removal of the lens in one piece along with the front
portion of the lens capsule. This procedure is still utilized, but
in limited circumstances due to the larger more invasive incision
needed. Phacoemulsification small incision cataract surgery is
essentially the standard of care. The surgery utilizes ultra sound
energy to fragment the lens so it can be evacuated through the
small incision port. The technique employs a foldable posterior
chamber interocular lens (PCIOL) to facilitate transplantation
through the small incision. The PCIOL is positioned in the
remaining lens capsule structure and centrally positioned by
flexible haptics. This small incision technique has generally
replaced other procedures. It is noted that there are a wide
variety of PCIOL's available in various designs and materials.
Surgeons have significant surgical liberties in the cataract
extraction field. Foldable anterior chamber interocular lenses
(ACIOL) have recently been developed. These lenses are employed by
the same small incision technique. They are placed in the anterior
chamber and positioned by flexible haptics resting in the anterior
chamber angle. ACIOL's are generally designed to be used in phakic
eyes as they are positioned in the chamber anterior to the lens.
This is usually an elective procedure to correct high or difficult
prescriptions. The procedure is resorted to when other refractive
devices or surgical options are not possible or have limited
potential.
[0019] The market for elective refractive surgery is well
established. Refractive surgery without device implantation
includes: Radial Keratotomy (RK), Astigmatic Keratotomy (AK),
Photo-Refractive Keratectomy (PRK) and Laser Assisted In-Situ
Keratomileusis (LASIK). RK and AK involve carefully placed
superficial incisions into the corneal stroma in a radial fashion.
These procedures are not performed anymore, and are predecessors
that led to PRK and LASIK. The utilization of lasers with PRK and
LASIK has much greater control and predictable outcomes. Modern PRK
and LASIK are considered elective procedures. They can correct most
naturally occurring refractive errors. These are not truly
reversible techniques because tissue is removed with the laser.
[0020] The implantation of interocular lenses accounts for nearly
all of the devices implanted to correct refractive errors. The
laser surgery techniques dominate the tissue altering procedures by
re-shaping the cornea. Intra-stromal corneal rings are an
alternative option for low levels of myopia and astigmatism. Small
incisions in the corneal stroma are made. Two crescents or
semi-circular shaped ring segments are implanted on opposing sides
away from the central cornea. The embedding of the rings in the
cornea has the effect of flattening the cornea and changing the
refraction. Intacs are the FDA approved device for this procedure.
They are made of a relatively rigid material,
Poly(methylmethacrylate) (PMMA). Intacs have not gained significant
market share despite being marketed as a reversible procedure.
Presently they are often used for the treatment of Keratoconus.
Their semi-rigid structure offers support to a structurally failing
cornea. There is extensive data from photorefractive surgery and
cornea curvature altering proceeds. The cornea has an average
refractive power of 45 diopters. This high power along with 18
diopters from the natural lens is required to focus light to
produce images at the 24 mm axial length of the eye. The majority
of naturally occurring refractive errors are within a prescription
of one diopter. This is a very small amount with respect to the
total power of the system. A device with the ability to internally
expand along the corneal base would flatten corneal curvature
resulting in decreased myopia. The cornea only requires a
flattening of 75 microns to achieve a one diopter decrease in
myopia. Achieving such a flattening of the cornea would only
require an increase in diameter of 60 microns at the corneal
base.
[0021] The loss of accommodative ability remains one of great
interest within the field of refractive correction. The ability to
change focus provides the optical system control and an advantage
over any static approach. The development of a device to rejuvenate
the natural ineffective aged system is being actively perused. The
advantages of such a system could be more significant than the
visual control and clarity. Stability of the accommodative
musculature has the ability to relieve the retinal tension by
returning the system to equilibrium. Present techniques and
procedures under investigation to restore accommodation are either
external or internal to the posterior chamber. Externally there are
techniques that suggest the suturing of bands around the eye to
increase the diameter and provide a more rigid external base for
the ciliary muscles internally. The concept is to reduce flaccidity
of the zonular complex by external expansion to enable some
reaction to the accommodative actions of the ciliary muscles.
[0022] However, the eye is dynamic and changes in refractive status
do have predictable patterns as well changes that cannot be
anticipated. In theory, the eye cannot be static until it is
aphakic after cataract surgery. At this stage there is no effective
accommodation. The cortical connections and accommodative
musculature still remain, but no lens remains to facilitate a
response. Developing a way of utilizing the cortical and muscular
system to facilitate accommodation will be of great benefit. An
artificial lens is required to achieve this. Focusing PCIOL's are
in development and are already available. The lens is implanted in
the posterior chamber replacing the natural lens. The concept is to
have a lens with shape changing characteristics to harness the
movement of the ciliary muscle during accommodative stimulation.
These lenses will continue to develop, but presently have limited
success. Harnessing accommodative forces in the anterior chamber
would allow for the development of a shape changing lens implant in
front of the iris.
SUMMARY OF THE INVENTION
[0023] A stent device implanted into the anterior chamber angle
could provide various structural elements and forces to restore
some accommodative ability in the phakic eye. The stent must have
precise anatomical placement to achieve this. The positioning of
the stent is essentially along the internal foundation of the
cornea. In this position it can induce forces radiating outward and
anteriorly along the posterior cornea base. The forces would
translate to a re-positioning of the accommodative apparatus to a
more posterior placement. In this position the eye can restore some
level of accommodation. The forces applied at the corneal base can
also be adjusted to manipulate corneal curvature and change
refractive error.
[0024] In addition, the stent device implanted at the internal base
of the cornea could translate motion if it can articulate.
Embodiments of such a device would provide a base to implant the
novel concept of a focusing ACIOL. The stent device, along with the
additional here in claimed invention of the complimentary focusing
ACIOL, has the potential to provide pseudo-accommodation. This
configuration of an accommodating ACIOL will be discussed in
relation to the stent device but should not be limited to the
preferred embodiments to be discussed and illustrated. The concept
of an accommodating ACIOL is dependent on the specific anatomical
fitting of the stent device and as such is considered an extension
of this invention. The stent of the present invention is configured
to provide such features.
[0025] Therefore, generally provided is a surgically-implantable
device for the human (or mammalian) eye that addresses or overcomes
some or all of the deficiencies and drawbacks in the field of
medical eye care. Preferably, provided is a surgically-implantable
device for the human (or mammalian) eye that facilitates the
restoration of the architecture of the anterior chamber angle and
underlying accommodative apparatus. Preferably, provided is a
surgically-implantable device for the human (or mammalian) eye that
provides the eye with ability to restore, regenerate and rejuvenate
various elements of normal function. Preferably, provided is a
surgically-implantable device for the human (or mammalian) eye that
addresses the clinical need for a faster, safer and more cost
effective method to treat diseases and degenerative conditions of
the eye.
[0026] The anatomical area of implantation is very specific, but
within the anatomy there will be various embodiments of devices.
The description of preferred embodiments of this invention is not
limited to variations in design, materials, manufacturing and
procedures relating to implantation of the invention. Any
embodiment of this device will involve minimally invasive small
incision by clear cornea, modified clear cornea or scleral tunnel
implantation techniques. Preferred embodiments of this device would
be removable and thus enable reversal of failed procedures.
[0027] The device may be specifically fit according to the involved
anatomy and patient specific sizing with respect to this anatomy.
Recent refinements and advances in imaging technology are now
allowing for very accurate clinically available equipment. The
introduction of time domain anterior segment optical coherence
tomography (AS-OCT) technology allows for in vivo, cross-sectional
tissue imaging. This provides diagnostic and management
capabilities that is far superior then before. Prior to the
introduction of this technology in 2006, the only way to obtain
cross-sectional images of the anterior segment was with
histological sectioning The importance of this technology is
apparent when applying the specific anatomical placement of the
potential embodiments of the device.
[0028] In a preferred and non-limiting embodiment, an ocular stent
for insertion in an anterior chamber of an eye includes an annular
body. The body includes: an anterior portion configured to contact
a surface of a transition zone between a trabecular meshwork and a
corneal endothelium of the eye; a posterior portion configured to
contact a peripheral iris of the eye; and a central portion
connecting the anterior portion and the posterior portion of the
body.
[0029] In certain embodiments, the anterior limits of the device
may encroach on and make contact with the adjacent trabecular
meshwork and corneal endothelium. The posterior portion of the
device will be configured to be in contact with a portion of the
surface of the peripheral iris. The peripheral limits of the
posterior contact may extend around the anterior chamber
irideocorneal angle to cross the anterior chamber exposure of the
ciliary body up to or beyond the scleral spur to encroach on the
trabecular meshwork. The central range of the posterior contact
along the iris will be sufficient to support the range of the
ciliary body structure posterior to the iris. The anterior and
peripheral portions of the device will have structural connection
with configuration to maintain the device out of contact with the
majority (or other proportion) of the surface of the trabecular
meshwork.
[0030] Additionally, certain embodiments of this invention have a
grouping of objectives that are inherent to the action of
mechanically restoring anatomical architecture of the aging eye.
Implantation of the device will inevitably have multiple actions
regardless of the desired action. By design, the device cannot
single out any one objective without including the other
complimentary objectives. As such the device can be seen to have
the primary objective of reversing the natural aging processes with
respect to certain aspects of the eye.
[0031] In accordance with a further preferred and non-limiting
embodiment, an ocular stent for insertion in an anterior chamber of
an eye is provided. The stent includes: at least one annular cord;
a plurality of anterior arms extending from the cord in a first
direction; and a plurality of posterior arms extending from the
cord in a second direction, the second direction being different
than the first direction. The stent is configured to be receivable
within an irideocorneal angle of the anterior chamber of the eye.
Additionally, the anterior arms and the posterior arms together are
configured to form an articulating joint.
[0032] The above-describe exemplary embodiments of the invention
are provided for treatment of eye conditions related to aging. One
aspect of the invention relates to a medical device system for
treating the tissues of the trabecular meshwork. The trabecular
meshwork and the juxtacanilicular tissue collectively are
responsible for the resistance to the out flow of the aqueous
humor. The trabecular meshwork is thus a logical target for tissue
rejuvenation and stimulation for the treatment of glaucoma. The
various possible embodiments of the device all apply appositional
forces anterior and posterior to the trabecular meshwork. Preferred
embodiments may have partial contact with the trabecular meshwork.
Significant contact with the anterior portion of the trabecular
meshwork may produce increased stem cell activity. As such,
centering the anterior portion of the device at an anterior portion
of the trabecular network may provide improved results. Despite any
contact, the device will effectively span and open the structure to
enhance flow of the aqueous. Since there is no true treatment,
control of the disease is the goal. Lowering IOP by 20% relative to
pre-treatment levels is a general rule to measure initial
success.
[0033] Another aspect of the invention relates to stem cell
activation by appositional stimulation to the posterior limbus
transition zone. There is evidence of stem cells for the corneal
endothelium as well as stem cells for the trabecular meshwork
residing there. Successful stimulation has regenerative potential
for Fuchs' corneal dystrophy and glaucoma respectively.
Regeneration of trabecular meshwork tissues would be very
complimentary to the aforementioned structural aspect of the device
to increase outflow. Stimulation of the endothelial stem cells
offers promise as a potential treatment or prophylactic measure to
circumvent normal endothelial cellular loss with aging. Mechanical
stimulation of stem cells is well known in various tissues of the
body. Regular physical stimulation of tissues is often needed to
maintain the regenerative processes. The internal limbal transition
zone of the cornea does not have the same mechanical stimulation as
the external limbal area responsible for epithelial regeneration.
There is continual direct mechanical interaction with external eye
and perpetual regeneration is required to sustain healthy tissues
of the external eye. The internal transition zone must have
internal mechanical stimulation by translation of accommodative
energy. A child's excessive accommodative ability can translate
into forces greater than ten times that of the middle aged adult.
Embodiments of this device will have the ability to produce
variable amounts of appositional forces on the transition zone.
Although different in presentation than accommodative forces, it is
hypothesized that such appositional force will result in favorable
stem cell activity. Such activity can be easily measured as it
relates to endothelial cell density. Evaluation of the endothelium
by specular microscopy is a non-invasive way to achieve this.
[0034] Some other aspects of the invention relate to repositioning
and stabilization of the accommodative apparatus. The posterior
contact of the various embodiments is essential to the overall
function of the invention. The anatomical placement of this contact
is such to transfer an adequate amount of force through the iris
base to result in a posterior repositioning of the ciliary body.
This repositioning of the accommodative apparatus will be
restorative to some accommodative function. The ability to restore
focusing ability is a very desirable aspect of the device
embodiments. Calculations and adjustments will be patient specific
to achieve the desired results. Loss of accommodation is not
classified as a disease, but rather considered an inconvenient
result of aging. It is a degenerative condition that does relate to
the manifestation of disease processes. Implantation of an
embodiment of this device for the purposes of restoring
accommodation or changing refractive status will also have
benefit(s) of the additional aspects of the device.
[0035] Another attribute of the device relating to repositioning of
the accommodative apparatus is retinal stabilization. The physical
posterior shifting of the ciliary body will relieve excessive
tension translated to retinal attachments linked to the
accommodative apparatus. Restoring accommodative control is also a
significant part of reducing retinal detachment. Accommodative
control will allow for stable control of the ciliary muscle and
reduce or prevent ineffective unnecessary contractions. The various
embodiments will be able to be sized to achieve the desired effect
and reduce the risks associated with retinal detachments of this
etiology.
[0036] Embodiments of the invention can be designed to position an
AIOL. The specially designed lens can be retained in the base
structure of the invention. The implantation of such a lens would
be indicated with cataract extraction, but variation could be
employed with a phakic eye as well. The circumferential designs of
the invention, in its articulating foams, will allow for the
opportunity to develop a lens capable of changing its radius of
curvature and position in relation to natural accommodative
stimulation and muscular response. The ciliary body muscle induces
forces during accommodation that can allow the articulating
embodiment to induce small amounts of movement. The movement would
radiate inward upon contraction of the ciliary body with
accommodative stimulation. Accommodative feedback and ciliary
muscle action are still active even in the aphakic eye. There is no
response without the natural lens, or a PCIOL that is static.
Implantation of a lens that can tie into the feedback mechanisms
would return the control of focus. There is very significant prior
art with respect to implantable lenses. This design concept to work
with embodiments of the invention is a new concept that can utilize
acrylic and silicon-based materials. The design of this lens must
have sufficient ability to change curvature with small amounts of
movement allowing a functional accommodative range. It will require
a PCIOL of opposing power to complete the optical system.
Calculations based on pairing of lenses can produce accommodative
responses in excess of that required under normal visual demands.
Preferred embodiments of this complimentary device are to be
considered an extension of the original invention, and not to be
limited in design, materials or manufacturing process.
[0037] A variety of biocompatible materials can be employed to
manufacture the embodiments of the device and components of this
invention. The device may utilize such a variety of materials, many
of which have ongoing proven bio-compatibility in excess of 25
years. All embodiments of the device(s) are to be removable and
replaceable. The device(s) will be visible by mean of non-invasive
visual and imaging assessment. The following materials are examples
but not to be considered limiting for the design and manufacturing
of the device(s) and possible components of the invention. There
are a variety of proven biocompatible materials used in various
ocular implants. The original interocular lenses were made from
Polymethylmethacrylate (PMMA) and were not foldable. Presently, the
most common ocular implants are the posterior chamber interocular
lens (PCIOL). These are primarily made of silicone or acrylic and
often have PMMA components. The material of choice for single piece
embodiments must be bio-compatible, semi rigid, foldable and have a
constant memory of shape. A clear material would be cosmetically
favorable since the ring will be partially visible. It may also be
possible to color match or enhance the iris color. There is
significant debate over whether hydrophilic or hydrophobic
materials or surface treatments are superior. Some proven PCIOL's
utilize both properties. Potential materials may include:
Hydrophobic Acrylic, Hydrophilic Acrylic, Acrylic Polymer,
Silicone, Poly(styrene-block-isobutylene-block-styrene) SIBS,
Silicon Elastomer (Biosil), and Heparin Surface Modified Acrylics.
The annular design of the device can allow for very soft and
pliable materials to induce sufficient forces. The involved soft
tissues will require delicate and controlled contact. The
multi-piece embodiments can utilize a wider range of materials
since the individual components do not require the same flexibility
as those to be utilized in the single-piece embodiments. A proven
material, such as PMMA, can be utilized. It has rigid properties,
is extrudable and stable for laser cutting or lathe turning. Other
methods of manufacture can include: molding techniques, vacuum
forming, and solvent casting. Particular methods of manufacture
have not been disclosed. It is understood that a variety of
manufacturing methods do exist with substantial prior art in the
field of ocular implants. One or multiple methods of manufacture
may be employed in the manufacture of single or multiple components
of the possible embodiments of this invention. It may also be
useful to coat components of this device to enhance its functional
properties or biocompatibility. It may also be useful to coat the
device with therapeutic agents or implant a complimentary device
containing therapeutic agents.
[0038] According to a further aspect of the invention, a method of
stabilizing the irideocorneal angle of an anterior chamber of an
eye demarked by the cornea and iris is provided. The method
includes the step of inserting a stent into the anterior chamber,
such that the stent is in contact with soft tissue of the anterior
chamber. Following insertion of the stent, pressure is applied,
simultaneously, in an anterior direction to a surface of a
transition zone between an anterior limit of a trabecular meshwork
and a posterior limit of a corneal endothelium of the eye with an
anterior portion of the stent, and in a posterior direction to a
surface of the peripheral iris of the eye with a posterior portion
of the stent.
[0039] More particularly, implantation of the various possible
embodiments of the device would be in accordance to the prior art
of cataract surgery relating specifically to the implantation of
foldable interocular lenses. The present state of lens implantation
is highly developed, and those skilled in the art have a variety of
choices as to their preferences in materials and tools. Virtually
all implanted ocular lenses are foldable, allowing for small,
minimally-invasive, sutureless incisions. Smaller incisions that
allow quicker recovery, better wound strength and increased
surgical control, result in lower complication rates and better
outcomes. Diamond spade knives are used to make a 2-3 mm incision
through peripheral cornea or scleral tunnel techniques. The
interocular lenses are pushed through the small incision with a
variety of injector devices that usually consist of a cartridge
that prepares the lens by folding it and a plunger system to inject
it. Those skilled in the art can utilize these established devices
for purposes of implanting embodiments and components of the
device. Although new tools may not be needed for purposes of
implantation of the device(s), it will become apparent to those
skilled in the art which available devices are best suited as
techniques evolve. Refinements of the tools and techniques may lead
to development of specific new tools for implantation, manipulation
and removal of the various stent devices.
[0040] The embodiments of this medical device and methods are
provided in accordance of the objectives to rejuvenate or restore
elements of the eye. The disease processes and physiologic changes
herein mentioned above are as such detrimental to function. For
purposes of summarizing the invention, certain aspects, features
and advantages of the invention have been described. It is herein
to be understood that not all advantages of this invention may be
achieved in relation to any particular embodiment of the device(s)
or adjunctive components of the device(s). As such, the invention
may be embodied in configurations to optimize one or various
advantages. Implantation of the device may be indicated for any one
advantage or combination of advantages as indicated for treatment
or prophylactic intervention.
[0041] These and other features and characteristics of the present
invention, as well as the methods of operation and functions of the
related elements of structures and the combination of parts and
economies of manufacture, will become more apparent upon
consideration of the following description and the appended claims
with reference to the accompanying drawings, all of which form a
part of this specification, wherein like reference numerals
designate corresponding parts in the various figures. It is to be
expressly understood, however, that the drawings are for the
purpose of illustration and description only and are not intended
as a definition of the limits of the invention. As used in the
specification and the claims, the singular form of "a", "an", and
"the" include plural referents unless the context clearly dictates
otherwise.
[0042] Additional aspects and advantages of the invention will
become readily apparent to those skilled in the art upon reference
to the provided figures and detailed description of the preferred
embodiments. The invention is not limited to any particular
preferred embodiment(s) disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Some of the advantages and features of the preferred
embodiments of the invention have been summarized herein above.
These embodiments along with other potential embodiments of the
device will become apparent to those skilled in the art when
referencing the following drawings in conjunction with the detailed
descriptions as they relate to the figures.
[0044] FIG. 1 is a schematic sectional view of an eye showing
anatomical detail along with in situ placement of a stent, in
accordance with an aspect of the present invention;
[0045] FIG. 2 is a close up sectional view of FIG. 1 taken along
section 2-2, providing more anatomical detail of the superior
anterior segment of the eye relating to the stent, in accordance
with an aspect of the present invention;
[0046] FIG. 3 is a schematic sectional view of an eye showing
anatomical detail along with in situ placement of a stent, in
accordance with an aspect of the present invention;
[0047] FIG. 3A is a schematic sectional view of the eye and stent
of FIG. 3 taken along section 3-3, in accordance with an aspect of
the present invention;
[0048] FIG. 4A is a schematic illustration of a divided front view
of a stent illustrating continuous and/or divided variations of a
ring, in accordance with an aspect of the present invention;
[0049] FIG. 4B is a cross-section view of the stent of FIG. 4A
taken along section 4B-4B, in accordance with an aspect of the
present invention;
[0050] FIG. 4C is a partial side profile view of the stent of FIG.
4A taken along section 4C-4C and having drainage ports, in
accordance with an aspect of the present invention;
[0051] FIG. 4D is a cross-section view of the stent of FIG. 4A
taken along section 4D-4D, in accordance with an aspect of the
present invention;
[0052] FIG. 4E is a partial side profile view of the stent of FIG.
4A taken along section 4E-4E and illustrating a beaded anterior
surface, in accordance with an aspect of the present invention;
[0053] FIG. 5 is a schematic sectional view of an eye showing
anatomical detail along with in situ placement of a stent, in
accordance with an aspect of the present invention;
[0054] FIG. 5A is a schematic sectional detail of the eye and stent
of FIG. 5 taken along section 5-5 in accordance with an aspect of
the present invention;
[0055] FIG. 6A is a schematic front view of a stent illustrating a
single piece non-continuous ring with a continuous tensioning
O-ring in place, in accordance with an aspect of the invention;
[0056] FIG. 6B is a cross-section view of the stent of FIG. 6A
taken along section 6B-6B, according to an aspect of the present
invention;
[0057] FIG. 6C is a partial side profile view of the stent of FIG.
6A taken along section 6C-6C, in accordance with an aspect of the
present invention;
[0058] FIG. 7 is a schematic sectional view of an eye showing
anatomical detail along with in situ placement of a stent, in
accordance with an aspect of the present invention;
[0059] FIG. 7A is a sectional detail of the eye and stent of FIG. 7
taken along section 7-7 in accordance with an aspect of the present
invention;
[0060] FIG. 8A is a half section front view of the stent of FIG. 7
as a multi-piece continuously joined ring with a continuous
tensioning O-ring in place, in accordance with an aspect of the
invention;
[0061] FIG. 8B is a cross-section view of the stent of FIG. 8A
taken along section 8B-8B with illustrated anatomical detail shown,
in accordance with an aspect of the invention;
[0062] FIG. 8C is a partial side profile view of the stent of FIG.
8A taken along section 8C-8C with anatomical detail shown as it
would be seen in the irideocorneal angle by means of gonioscopy, in
accordance with an aspect of the invention;
[0063] FIG. 8D is a schematic drawing that illustrates details of
the articulating components of the stent of FIG. 8A, in accordance
with an aspect of the present invention;
[0064] FIG. 9A is a schematic section view of an aphakic eye
illustrating the stent of FIG. 7 in situ with an accommodating
anterior chamber interocular lens (ACIOL) and an adjunctive
stationary posterior chamber interocular lens (PCIOL), in
accordance with an aspect of the invention;
[0065] FIG. 9B is a schematic drawing of a quartered front view of
an eye illustrating the various details of the stent of FIG. 7 and
ocular anatomy, in accordance with an aspect of the invention;
[0066] FIG. 10A is a schematic drawing of a folding interocular
lens injector, which can be utilized for implantation of a stent,
in accordance with an aspect of the invention; and
[0067] FIG. 10B is a schematic drawing of a front view of an
implantation procedure, using the injector of FIG. 10A to inject a
stent, in accordance with an aspect of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0068] The illustrations generally show preferred embodiments of
the devices used to treat predictable structural ocular aging
changes of the anterior segment of the human eye. While the
descriptions present various embodiments of the device(s), it
should not be interpreted in any way as limiting the invention.
Furthermore, modifications, concepts and applications of the
inventions embodiments are to be interpreted by those skilled in
the art as being encompassed, but not limited to the illustrations
and descriptions herein.
[0069] The following description is provided to enable those
skilled in the art to make and use the described embodiments
contemplated for carrying out the invention. Various modifications,
equivalents, variations, and alternatives, however, will remain
readily apparent to those skilled in the art. Any and all such
modifications, variations, equivalents, and alternatives are
intended to fall within the spirit and scope of the present
invention. Further, for purposes of the description hereinafter,
the terms "end", "upper", "lower", "right", "left", "vertical",
"horizontal", "top", "bottom", "lateral", "longitudinal" and
derivatives thereof shall relate to the invention as it is oriented
in the drawing figures. However, it is to be understood that the
invention may assume various alternative variations and step
sequences, except where expressly specified to the contrary. It is
also to be understood that the specific devices and processes
illustrated in the attached drawings, and described in the
following specification, are simply exemplary embodiments of the
invention. Hence, specific dimensions and other physical
characteristics related to the embodiments disclosed herein are not
to be considered as limiting. For the purpose of facilitating
understanding of the invention, the accompanying drawings and
description illustrate preferred embodiments thereof, from which
the invention, various embodiments of its structures, construction
and method of operation, and many advantages may be understood and
appreciated.
[0070] A sectional view of an eye is illustrated in FIG. 1. The
ocular stent 18 in this anatomical placement represents certain
preferred and non-limiting embodiments. It is positioned in the
anterior chamber of the eye. This chamber is bound by the cornea 32
anteriorly and the iris 29 posteriorly. Aqueous humor 31 fills and
circulates through this chamber. The cornea 32 is a clear
collagenous tissue responsible for most of the focusing ability of
the eye. It transitions into the white collagenous tissue of the
sclera 23 along the limbus 33. The lens 30 is suspended by the
zonular complex 28. The zonules 28 are ligamentous having their
muscular attachments to the ciliary body 27 and opposing attachment
into the equatorial region of the lens 30. The ciliary body 27 is
the muscular component of the accommodative complex. Along with the
ciliary body 27 and iris 29, the choroid 24 forms the uveal tract.
The choroid 24 is the highly vascular layer which underlies the
retina 20. The retina 20 is centrally bound by the vitreous body,
which is filled with vitreous humor 25. This central body makes up
the bulk of the volume of the eye. It maintains the eye's shape and
plays a role in accommodation. The central visual axis intersects
the retina 20 at the fovea 22 of the macular region. This region is
the most visually sensitive and innervated area of the retina 20.
All innervations and vascularisation of the eye is connected to the
brain via the optic nerve 21.
[0071] In FIG. 2, the anterior segment of the eye is shown with
additional anatomical detail around a preferred and non-limiting
embodiment of the ocular stent 18. The drainage structure of the
trabecular meshwork 17 and Schlemm's canal 19 are illustrated. The
corneal endothelium 16 is illustrated as are the anterior 34 and
posterior 35 lens capsules. The zonular attachments to the lens 30
and ciliary body 27 are divided into the anterior zonules 36,
equatorial zonules 37, posterior zonules 38 and hyaloid zonules 39.
The anterior hyaloid vitreous membrane 40 is the anterior boundary
of the vitreous humor 25.
[0072] FIG. 3 is a detailed illustration of a preferred and
non-limiting embodiment the ocular stent 18 in relation to adjacent
anatomy. The ocular stent 18 is implanted in the peripheral
irideocorneal angle 44 of the anterior chamber, having an anterior
portion configured to be centered on and in contact with the
surface of the transition zone 42 between the anterior limits of
the trabecular meshwork 17 and posterior limits of the corneal
endothelium 16 or posterior aspect of the limbus 41. The anterior
limits of the ocular stent 18 may encroach on and make contact with
the adjacent trabecular meshwork 17 and corneal endothelium 16. The
posterior portion of the ocular stent 18 will be configured to be
in contact with a portion of the surface of the peripheral iris 29.
The peripheral limits of the posterior contact may extend around
the anterior chamber irideocorneal angle 44 to cross the anterior
chamber exposure of the ciliary body 27 up to or beyond the scleral
spur 43 to encroach on the trabecular meshwork 17. The central
range of the posterior contact along the iris 29 will be sufficient
to effectively support the ciliary body 27 structure posterior to
the iris 29. The ocular stent 18 may be formed with a boomerang
shaped radial cross section. In that case, the anterior portion and
the posterior portion of the ocular stent meet at a central portion
12. As will be appreciated by those having skill in the art, the
central portion 12 may be integrally formed with the anterior and
posterior portions of the body. Alternatively, the central portion
12 may be a joint, such as an articulating joint.
[0073] As will be appreciated by one having ordinary skill in the
art, the stent 18 may be able to reposition and retain the position
of the ciliary body 27. For example, in the embodiment depicted in
FIG. 3, the ocular stent 18 is positioned in the anatomy of the eye
to enable favourable function. The ocular stent 18 spans the
filtering structure of the trabecular meshwork 17 expanding and
opening its porous structure. This structurally supported
configuration of the drainage anatomy will decrease IOP and promote
rejuvenation of the tissues. In certain embodiments, the ocular
stent 18 is composed of a biocompatible material that has
structurally stable properties. The integrity of the anatomical
organization will remain since the properties of the ocular stent
18 are required to be stable. These stable properties also will
allow for consistent and accurate contact with the transition zone
42. This is required to induce appropriate forces at this area of
stem cell activity. The appositional stimulation of stem cells here
can impact regeneration of corneal endothelial cells 16 and cells
pertaining to the trabecular meshwork 17. The posterior aspect of
the ocular stent 18 is configured to assist in positioning of the
trabecular meshwork 17 and transition zone 42. This posterior
contact along the iris 29 base translates forces required to
reposition the ciliary body 27 and variable forces from muscular
action in the ciliary body 27 to the transition zone 42. The
posterior repositioning shifts the accommodative structure
posteriorly which in turn requires the structures to expand
circumferentially. This expansion will translate into a tightening
of the posterior 38, equatorial 37, and anterior 36 zonules. The
return of tension to these zonules will result in some degree of
accommodative function. The return of function will stabilize
muscular action by means of effective feedback and control of the
ciliary body 27. This is important as it relates to the hyaloid
zonules 39. The posterior movement of the ciliary body 27 will
relieve excessive tension on the hyaloid zonules 39. This combined
with returned control of the accommodative musculature will relieve
excessive tension being transferred to the hyaloid retinal
connections and thus reduce the risk of retinal detachment. The
stent 18 requires very specific sizing and anatomical placement. It
will be possible to adjust the sizing to induce forces to enable
some manipulation of refractive error. More specifically, the
ocular stent 18 is positioned at the base of the cornea 32. This
area of circumferential placement is the foundation of the cornea
and as such the structural base of the cornea 32.
[0074] A divided front view of a preferred and non-limiting
embodiment of the ocular stent 18 is shown in FIGS. 4A-4E, for
purposes of illustrating various embodiments of the stent 18. FIG.
4A illustrates a half section of a continuous variation of the
ocular stent 18 having a communication structure, such as ports 14.
As used herein, a "communication structure" refers to a structure
such as a port, tube, opening, or through hole extending through
the body of the stent 18 for permitting fluid to pass therethrough.
The ports 14 equalize fluid pressures across the ocular stent 18.
Six ports 14 are illustrated to convey the concept. The size and
number of ports 14 can be varied to achieve a desired result. A
single port 14 could be adequate to provide sufficient flow, but
continued patency would be a concern so multiple ports 14 may be
utilized. The ports 14 have the potential to reduce or virtually
eliminate pigment dispersion into the trabecular meshwork 17. A
superior placement of the ports 14 reduces pigment transfer
allowing free pigment to settle inferiorly blocked by the ocular
stent 18 from passing into the drainage structures. FIG. 4A
illustrates a half section of a non-continuous variation of the
ocular stent 18 having a beaded or textured anterior surface 15.
The ocular stent can be segmented in either variation but is only
illustrated in FIG. 4A. Having a small segment removed creates an
internal snap ring design. This variation in design would allow for
greater variability in fitting the ocular stent 18. The tensile
modulus of the ocular stent 18 would allow for some variability in
diameter and induced forces from a particular size. The removed
segment will also provide direct access to the structures of the
anterior chamber angle. It would be possible to implant a stent
that penetrates the trabecular meshwork 17 to provide direct flow
of the aqueous humor 31 to Schlemm's canal 19. The non-segmented
variation would have virtually no variability and require precise
sizing. The beaded or textured anterior surface 15 provides
variable contact along the contact surface, allowing for
equalization of fluid pressure across the ocular stent 18. This
would be required in the case of a continuous ring design. The
beading texture 15 also servers the purpose of providing a
non-continuous surface in contact with the transition zone 42.
Variations in the texture can be manipulated to achieve
optimization of the appositional stem cell stimulation.
[0075] FIG. 4B is a sectional view of ocular stent 18 with the
sectional view of a port indicated by the dashed lines. FIG. 4C is
a partial side profile view of the ocular stent 18 as it would be
viewed from inside the anterior chamber of the eye with the port
openings visible. The illustrated view orientating is indicated in
FIG. 4A. FIG. 4D is a sectional view of ocular stent 18 with the
beading contour indicated. FIG. 4E is a partial side profile view
of the ocular stent 18 as it would be viewed from inside the
anterior chamber of the eye with the anterior beaded surface
visible. The illustrated view orientating is indicated in FIG.
4A.
[0076] With reference to FIG. 5, a preferred and non-limiting
embodiment of an ocular stent 47 is depicted. The ocular stent 47
is implanted in the peripheral irideocorneal angle 44 of the
anterior chamber. The ocular stent 47 has an anterior portion
configured to be centered on and in contact with the surface of the
transition zone 42 between the anterior limits of the trabecular
meshwork 17 and posterior limits of the corneal endothelium 16 or
posterior aspect of the limbus 41. The anterior limits of the
ocular stent 47 may encroach on and make contact with the adjacent
trabecular meshwork 17 and corneal endothelium 16. The posterior
portion of the ocular stent will be configured to be in contact
with a portion of the surface of the peripheral iris 29. The
peripheral limits of the posterior contact may extend around the
anterior chamber irideocorneal angle 44 to contact the anterior
chamber exposure of the ciliary body 27 up to or beyond the scleral
spur 43 to encroach on the trabecular meshwork 17. The central
range of the posterior contact along the iris 29 will be sufficient
to effectively support the ciliary body 27 structure posterior to
the iris 29. As in previously described embodiments, the stent 47
is configured to reposition and retain the position of the ciliary
body 27. The ocular stent 47 spans the filtering structure of the
trabecular meshwork 17 expanding and opening its porous structure.
This structurally supported configuration of the drainage anatomy
will decrease TOP and promote rejuvenation of the tissues. In
certain embodiments, the ocular stent 47 is composed of
biocompatible materials that are relatively soft and flexible. The
ocular stent 47 is designed to incorporate an O-ring 48 to provide
the structure with stability and ability to alter induced forces
with respect to the anatomical arrangement of the involved
structures. These stable properties also will allow for consistent
and accurate contact with the transition zone 42. This is required
to induce appropriate forces at this area of stem cell activity.
The appositional stimulation of stem cells here can impact
regeneration of corneal endothelial cells 16 and cells pertaining
to the trabecular meshwork 17. The posterior aspect of the ocular
stent 47 is essential to the aforementioned actions on the
trabecular meshwork 17 and transition zone 42. This posterior
contact along the iris base 29 translates forces required to
reposition the ciliary body 27 and variable forces from muscular
action in the ciliary body 27 to the transition zone 42. The
posterior repositioning shifts the accommodative structure
posteriorly which in turn requires the structures to expand
circumferentially. This expansion will translate into a tightening
of the posterior 38, equatorial 37 and anterior 36 zonules. The
return of tension to these zonules will result in some degree of
accommodative function. The return of function will stabilize
muscular action by means of effective feedback and control of the
ciliary body 27. This is important as it relates to the hyaloid
zonules 39. The posterior movement of the ciliary body 27 will
relieve excessive tension on the hyaloid zonules 39. This combined
with returned control of the accommodative musculature will relieve
excessive tension being transferred to the hyaloid retinal
connections and thus reduce the risk of retinal detachment. In a
preferred and non-limiting embodiment, the ocular stent 47 requires
specific sizing and anatomical placement, but has significant
adjustment due to the O-ring 48 component. It will be possible to
adjust the sizing to induce forces to enable some manipulation of
refractive error. The ocular stent 47 is positioned at the base of
the cornea 32. This area of circumferential placement is the
foundation of the cornea and as such the structural base of the
cornea 32. The properties of the materials utilized for the ocular
stent 47 and the O-ring 48 along with the amount of tensioning can
be manipulated to create some movement of the O-ring 48 with
accommodative stimulation. This motion can be utilized to
incorporate an accommodating anterior chamber interocular lens
(ACIOL).
[0077] A front view of a preferred and non-limiting embodiment of a
stent is shown in FIG. 6A. FIG. 6A illustrates placement of the
continuous O-ring 48 in the non-continuous variation of the collar
stent 47 having an anterior aspect that is crenellated or notched.
These crenellations 45 have a similar function to the function of
the beaded surface 15 described previously. The crenellations 45
leave voids along the contact surface, allowing for aqueous flow
across the ocular stent 47. The aqueous pressure does not depend on
these crenellations 45 to equalize pressure. The void section of
the ocular stent 47 would provide sufficient flow on its own. The
crenellations 45 of the ocular stent 47 also serve the purpose of
creating a non-continuous surface in contact with the transition
zone 42. Variations in the texture can be manipulated to achieve
optimization of the appositional stimulation of stem cells. It
would be possible to produce non-crenellated variations. Such
variations would work similar to the ported version of the
previously described embodiments of the stent 47. In this case the
void section of the ocular stent 47 is oriented up to minimize
transfer of free pigment and debris. This orientation is
recommended for implementations including, but not limited to,
pigmentary glaucoma, pigment dispersion syndrome, and
pseudoexfoliative glaucoma.
[0078] FIG. 6B is a sectional view of the ocular stent 47 with a
sectional view of the O-ring 48 in position. The ocular stent 47 is
designed to allow for some translation of movement induced by
accommodative forces. FIG. 6C is a partial side profile view of the
ocular stent 47 as it would be viewed from inside the anterior
chamber of the eye with the O-ring 48 and crenellations 45 visible.
The illustrated view orientating is indicated in FIG. 6A. Parts of
the trabecular meshwork 17 anatomy will be visible through the
crenellations 45.
[0079] FIG. 7 is a detailed illustration of the invention showing a
preferred and non-limiting embodiment of an ocular stent 47 in
relation to adjacent anatomy. The stent 47 is assembled from
multiple pieces of three components: anterior arms 50, posterior
arms 51 and annular cords, such as beading lines 52 (shown in FIG.
8C). The arms 50, 51 connect at a joint 49, such as an articulating
joint. The assembled components collectively create an articulating
base. An O-ring 48 is positioned within the implanted articulating
base. The stent 47 is implanted in the peripheral irideocorneal
angle 44 of the anterior chamber, such that the anterior aspect of
the anterior aim 50 is designed to be centered on and in contact
with the surface of the transition zone 42 between the anterior
limits of the trabecular meshwork 17 and posterior limits of the
corneal endothelium 16 or posterior aspect of the limbus 41. The
anterior limits of the ocular stent 47 may encroach on and make
contact with the adjacent trabecular meshwork 17 and corneal
endothelium 16. The peripheral portion of the anterior arm 50 and
peripheral portion of the posterior arm 51 are designed to be
connected. This connection area extends around the anterior chamber
irideocorneal angle 44 to contact the anterior chamber exposure of
the ciliary body 27 up to or beyond the scleral spur 43 to encroach
on the trabecular meshwork 17. The posterior arm 51 is configured
to be in contact with a portion of the surface of the peripheral
iris 29. The central range of the posterior contact along the iris
29 will be sufficient to effectively support the ciliary body 27
structure posterior to the iris 29. The stent 47 is configured to
reposition and retain the position of the ciliary body 27. As shown
in FIG. 7A, the stent 47 is well positioned anatomy to enable
favourable function. The anterior arm 50 spans the filtering
structure of the trabecular meshwork 17 expanding and opening its
porous structure. This structurally supported configuration of the
drainage anatomy will decrease IOP and promote rejuvenation of the
tissues. The anterior 50 and posterior 51 arms of the ocular stent
are to be composed of a biocompatible material that is relatively
rigid. Polymethylmethacrylate (PMMA) is a suitable material;
however, the ocular stent 47 components are not limited to PMMA.
The material may have shape memory characteristics. As used herein,
"shape memory" refers to a material which returns to an initial
shape when biasing forces are removed therefrom. Shape memory may
also refer to a material which returns to an initial shape as a
result of a triggering event such as when the material is heated to
a specific predetermined temperature. The incorporated O-ring 48
provides the ability to alter induced forces with respect to the
anatomical arrangement of the involved structures. The combination
of components produces a stable structure able to articulate at the
irideocorneal angle 44. The relatively stable properties also allow
for consistent and accurate contact of the anterior arm 50 with the
transition zone 42. This contact is required to induce appropriate
forces at this area of stem cell activity. The appositional
stimulation of stem cells here can impact regeneration of corneal
endothelial cells 16 and cells pertaining to the trabecular
meshwork 17. The anterior arm 50 of the ocular stent is essential
to the aforementioned actions on the trabecular meshwork 17 and
transition zone 42. This posterior contact along the iris base 29
translates forces required to reposition the ciliary body 27 and
variable forces from muscular action in the ciliary body 27 to the
transition zone 42. The posterior repositioning shifts the
accommodative structure posteriorly which in turn requires the
structures to expand circumferentially. This expansion translates
into a tightening of the posterior 38, equatorial 37, and anterior
36 zonules. The return of tension to these zonules results in some
degree of accommodative function. The return of function will
stabilize muscular action by means of effective feedback and
control of the ciliary body 27. This is important as it relates to
the hyaloid zonules 39. The posterior movement of the ciliary body
27 relieves excessive tension on the hyaloid zonules 39. This
combined with returned control of the accommodative musculature
will relieve excessive tension being transferred to the hyaloid
retinal connections and thus reduce the risk of retinal detachment.
The stent 47 requires specific sizing and anatomical placement, but
has significant adjustment because its multi piece construction and
O-ring 48 component. For example, it is possible to adjust the
sizing of the stent 47 to induce forces to enable some manipulation
of refractive error. The ocular stent 47 is positioned at the base
of the cornea 32. This area of circumferential placement is the
foundation of the cornea and, as such, the structural base of the
cornea 32. The ability of stent 47 to articulate can enable it to
harness and translate accommodative force to produce movement of
the O-ring 48. This motion can be utilized to incorporate an
accommodating anterior chamber interocular lens (ACIOL).
[0080] A half section front view of the stent 47 is shown in FIG.
8A. The stent 47 depicted in FIG. 8A illustrates the continuous
beading together of the alternating anterior arm 50 and posterior
arm 51 components. Placement of the O-ring 48 is also illustrated.
The alternation of the components produces voids, allowing for free
aqueous flow throughout the ocular stent. This is an advantage with
respect to freedom of flow more representative of the natural
anatomy. In the case of pigment dispersion syndrome and pigmentary
glaucoma, this embodiment would not be the preferred one. This
configuration cannot provide any pre-filtering properties as in the
previously described embodiments of the stent. The alternating
structure also serves the purpose of creating a non-continuous
surface in contact with the transition zone 42 and iris base 29.
The alternating pattern provides a variation of the appositional
stimulation of stem cells.
[0081] FIGS. 8B and 8C are schematic views of the stent 47 in situ
with illustrative anatomy. The relationship between the O-ring 48,
the anterior arm 50, the posterior arm 51 and anatomy is shown for
the purpose of relating to FIG. 8C. FIG. 8C is a partial side
profile view of the stent 47 as it would be viewed from inside the
anterior chamber of the eye with anatomy visible. The stent 47 has
the advantage of leaving some of the anatomy visible through the
voids. It is noted that all of the embodiments of the stent
described herein can be viewed by gonioscopy; however, the stent 47
depicted in FIGS. 7-8D has the most anatomy visible. The partial
side view of the components has been staggered to illustrate the
relationship between the components. This view best illustrates
that the beading lines 52 tie the components together. As shown in
FIG. 8C, three beading lines 52 are required to assemble the
components. The triplication provides security that this embodiment
will remain intact once assembled. FIG. 8D illustrates side and
front views of the anterior arm 50 and posterior arm 51 separated
as individual units. The holes used for beading are shown. The
anterior arm 50 has three round holes 53, while the posterior arm
has two round holes 53 and one slotted hole 54. The purpose of the
slotted hole 54 is to allow articulating but limit range of motion.
Such a limit on the range of motion is required to prevent the
ocular stent from folding in on itself during implantation. The
arms of the ocular stent 47 must remain open enough to insert the
O-ring 48.
[0082] FIG. 9A is a sectional view of an aphakic eye illustrating
the stent 47 with an articulating joint 49. The implantation of an
accommodating ACIOL is illustrated as it would be implanted and fit
to the stent 47. The ACIOL body 57 illustrates the positioning of
the ACIOL when the accommodative musculature is relaxed and 57'
illustrates the ACIOL's change in position and curvature under
accommodative stimulus. Articulation of the posterior arm 51
translates the accommodative contractions into small amounts of
movement of the O-ring 48'. The O-ring 48' is incorporated into the
ACIOL design becoming the peripheral limits of the ACIOL. The
O-ring 48' is circumferentially fused with the extended anterior
surface 55 of the ACIOL. The ACIOL has its optical form completed
by its posterior surface 56. The two surfaces of the accommodating
ACIOL could be manufactured from acrylic material that is then
filled with index matched silicone oil or material of similar
properties. These material properties will enable the vaulted ACIOL
to change curvature with minor movement. Model tests and
calculations indicate a decrease in diameter of 200 microns would
potentially induce 10 diopters of accommodation. The refractive
power of the ACIOL will need to be greater than the power of the
human lens to produce sufficient levels of accommodation. In order
to create an effective optical system of the appropriate total
power a PCIOL 58 of opposing power will be required to complete
this dual optic design.
[0083] FIG. 9B illustrates frontal view of the anatomy and the
stent 47 with an accommodating ACIOL. The view is divided into
quarters A, B, C, D. The first quarter A illustrates this
embodiment independent of any anatomy. The alternating anterior
arms 50 and posterior arms 51 along with the O-ring 48 are visible.
The second quarter B represents the ocular anatomy without any
stents implanted. The third quarter C illustrates the complete
system of the stent 47 and the accommodation ACIOL components.
Components visible would include partial views of the anterior 50
and posterior 51 arms. Although predominantly clear, the body of
the ACIOL 57 and its anterior 55 and posterior 56 surfaces would be
in view. The fourth quarter D has the complete assembly of
components illustrated with the anatomy removed. An artificial
pupil ring is indicated by 59. Because the optics of the ACIOL are
anterior to the natural pupil it is optically advantageous to
create a boundary between the refractive and non refractive aspects
of the ACIOL.
[0084] FIG. 10A is an exemplary injector. Generally, the injector
consists of a main body 60 that houses the plunger mechanism 62.
The plunger has a silicon stopper 63, which is required to create
the hydraulic pressure of the viscoelastic gliding agent used to
eject the folded stent 18, 47 and/or the folded O-ring 48 from the
chamber. The injector cartridge 61 opens allowing the ocular stent
18, 47 to be positioned carefully and flooded with viscoelastic
before folding. In this illustration the O-ring 48 is being
prepared for implantation. It may be required to push part of the
O-ring 48 in to the cartridge tip 61' prior to folding. This will
depend on the length of the cartridge tip 61'.
[0085] In FIG. 10B a front view of the implantation procedure is
illustrated. Here the eye has been prepared with eyelid speculums
64 in place and the incision wound 65 made. This illustration shows
the stent 47 with its base structure already implanted. The
anterior 50 and posterior 51 arms are partially visible in the
anatomy, but clearly visible in the section where the anatomy has
been removed for illustrative purposes. The O-ring 48 is seen as it
is ejected from the cartridge tip 61'. The plunger 62 and the
silicone stopper 63 creating the hydraulic viscoelastic pressure
are also visible.
[0086] Discussion of this invention is made in relation to the
human eye, but it is appreciated that the invention described
herein is not limited or exclusive of the human eye. While specific
embodiments of the invention have been described in detail, it will
be appreciated by those skilled in the art that various
modifications and alternatives to those details could be developed
in light of the overall teachings of the disclosure. Accordingly,
the particular arrangements disclosed are meant to be illustrative
only and not limiting as to the scope of invention which is to be
given the full breadth of the claims appended and any and all
equivalents thereof. Further, although the invention has been
described in detail for the purpose of illustration based on what
is currently considered to be the most practical and preferred
embodiments, it is to be understood that such detail is solely for
that purpose and that the invention is not limited to the disclosed
embodiments, but, on the contrary, is intended to cover
modifications and equivalent arrangements that are within the
spirit and scope of the appended claims. For example, it is to be
understood that the present invention contemplates that, to the
extent possible, one or more features of any embodiment can be
combined with one or more features of any other embodiment.
* * * * *